There is a "strong case" for Boris Johnson to remain "in office" despite growing calls for him to resign over the ongoing partygate scandal as the PM has "plenty more fuel in the tank", Oliver Dowden has said.
The Conservative Party chairman told Sky News' Sophy Ridge on Sunday programme that Mr Johnson is "getting those big calls right" and said the "uncertainty" that would be caused by a change of leader "would be dearly damaging to this country".
Mr Dowden also reiterated that he does not believe the prime minister misled parliament.
It comes after MPs agreed that the PM should face a parliamentary investigation into whether he misled MPs when he denied lockdown rules were broken across Downing Street and Whitehall.
On Thursday, a Labour-led motion calling for the Privileges Committee to investigate Mr Johnson's conduct was nodded through without a vote.
The investigation will not fully begin until the conclusion of the Metropolitan Police's inquiry into 12 events and the Privileges Committee will determine whether the PM is in contempt of parliament for allegedly misleading MPs with his repeated denials of parties in Downing Street.
Asked whether the PM would have to quit if the Commons Privileges Committee finds that he lied to MPs over partygate reassurances, Mr Dowden said: "I don't believe the prime minister misled parliament.
"He is perfectly open to the Privileges Committee to conduct that investigation and parliament consented to that, so I don't believe that scenario will arise."
Pressed further, he added: "I think the prime minister is doing a really important job - whether that is what you saw in India this week in terms of agreeing the trade deal, continuing to tighten the pressure in Ukraine - so I think there is a very strong case for the prime minister remaining in office.
"But, as you alluded to, you would expect me to say it is a hypothetical scenario, so I'm not going to get into commentary on that."
'He's got real energy to continue to serve'
Expressing confidence that Mr Johnson will lead his party "into the next election", Mr Dowden said he shared "people's frustration over what happened".
"But I do think that needs to be balanced out both against what has already been achieved - whether that's the vaccine programme, that's Ukraine or delivering Brexit.
"The prime minister is getting those big calls right. But also, talking to the prime minister, he's got plenty more fuel in the tank.
"He's got real energy and determination to continue to serve this country and deal with some of the big challenges we face, whether that's levelling up or whether that's recovering from this, a global energy crisis and this national security crisis.
"And I think the uncertainty that would be caused by a change of leader would be dearly damaging to this country."
The PM has faced repeated questions about his future as the scandal continues to dog him despite his attempts to move on to broader issues during his trip to India earlier this week.
PM under continued pressure over partygate
Despite further rumblings of discontent within his own party over lockdown-busting parties that took place across Downing Street and Whitehall, the PM was adamant on Friday that he will still be prime minister in six months' time.
The prime minister returned to the UK on Saturday morning to the news of more of his own backbench MPs calling for him to resign and the Metropolitan Police having reportedly issued more partygate fines.
On Friday, Robert Largan became the latest of more than a dozen Tory MPs to speak out against Mr Johnson, telling constituents in a newsletter that he "will not defend the indefensible".
Earlier this week, former minister Steve Baker, an influential Conservative MP, said the prime minister "should be long gone".
Meanwhile, fellow Conservative MP and Public Administration and Constitutional Affairs Committee chairman, William Wragg, confirmed he had submitted a letter of no confidence in Mr Johnson's leadership.
"I cannot reconcile myself to the prime minister's continued leadership of our country and the Conservative Party," he told MPs in a scathing Commons speech.
Senior Tory MPs call for PM to resign
Another backbencher, Tobias Ellwood - who has already called on Mr Johnson to go, said there had been a "silence of support" and urged Conservatives to "take matters into their own hands".
It was understood on Friday that at least one Number 10 official had received a fixed penalty notice from the Met Police for attending a lockdown-busting "bring your own booze" event held in the Downing Street garden.
It is not known who has been fined for the gathering which was held at the height of the UK's first national lockdown on 20 May 2020, but on Friday Number 10 told Sky News that Mr Johnson had not at this stage been issued with a second fine over partygate.
Mr Johnson has previously admitted attending the garden drinks, but has repeatedly stressed he believed it was a "work event".
The prime minister apologised to MPs in January for being among those at the Downing Street drinks party, saying he spent 25 minutes thanking staff, before returning to his office.
Until now, it was known that more than 50 fines had been issued in relation to the lockdown-breaking parties in Westminster.